Mass transfer in a non-uniform impinging jet.

by Myndert Trevor Scholtz in [Toronto]

Written in English
Published: Pages: 284 Downloads: 252
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Subjects:

  • Jets,
  • Mass transfer

Edition Notes

ContributionsToronto, Ont. University.
Classifications
LC ClassificationsLE3 T52 PHD 1965 S365
The Physical Object
Paginationxi, 284 leaves.
Number of Pages284
ID Numbers
Open LibraryOL14743985M

Convective heat transfer to an impinging air jet is known to yield high local and area averaged heat transfer coe–cients. The current research is concerned with the mea-surement of heat transfer to an impinging air jet over a wide range of test parameters.   Book Search tips Selecting this option will search all publications across the Scitation platform Selecting this option will search all publications for the Publisher/Society in context. Pamadi, B. N. and Belov, I. A., “ A note on the heat transfer characteristics of circular impinging jet,” Int. J. Heat Mass Transfer 23(6), In this study, we apply the optical flow method to the time-series shadowgraph images of impinging jets using a high-speed video camera with high spatial and temporal resolution. This image analysis provides quantitative velocity vector fields in the object space without tracer particles. The analysis results clearly capture the details of the coherent vortex structure and its advection from. Local heat transfer for jet impingement onto a concave surface including injection nozzle length to diameter and curvature ratio effects Experimental Thermal and Fluid Science, Vol. 92 Effect of tangential jet impingement on blade leading edge impingement heat transfer.

  This paper presents extensive acoustic measurements on jets impinging on surfaces of various surface roughness values. Besides surface roughness, the effects of nozzle-to-plate spacing distance and nozzle pressure ratio are also investigated. Turbulent mixing noise and tonal noise are explained using far-field wall-jet velocity and impingement region temperature fields.   Heat and Mass Transfer 51(). 3. Chiriac V.A., Ortega A., “A numerical study of the unsteady flow and heat transfer in a transitional confined jet impinging on isothermal surface”, International Journal of Heat & Mass Transfer, 45() 4.   Impinging jet introduces high velocity of fluid stream to the impinged surface, leading to the high momentum transport and consequently high heat transfer rate on the surface [1, 2]. Several experimental and numerical studies have shown the ability to improve the heat transfer through the implementation of multiple swirling jet system. istics of both a free and an axially symmetric impinging air jet have been presented by Donaldson and Snedeker [4], Beltaos [5] and Martin [6]. In many investigations, includ-ing that by Gardon and Akfirat [7], the heat transfer to an impinging jet has been correlated with .

The results show that jet velocity plays a significant role in impingement cooling. For a given liquid mass flux and jet array configuration (e.g., the seven-jet configuration), an increase in velocity increased the heat transfer rate. () that the inherently non-uniform heat transfer distribution of jet arrays had little effect on the.   The coaxial jet causes higher and more uniform heat transfer over the impingement surface compared to that for a single jet. The swirl affects the mixing and jet spreading, which in turn modifies the heat transfer process resulting in diminished or enhanced heat transfer compared to a non-swirling jet. Book Chapters. Rau, M. J., Garimella, S. V., , Two-Phase Jet Impingement: Liquid-Vapor Interactions and Heat Transfer Mapping for Multiscale Surface Enhancement Design, Encyclopedia of Two-Phase Heat Transfer and Flow, Set 3, pp. , World Scientific Publishing Company. Reviewed Conference Proceedings. Heat transfer due to an axisymmetric laminar gas jet impinging onto a flat solid surface of uniform temperature is studied numerically, taking into account the temperature dependence of all fluid physical properties. Numerical solutions are obtained for the jet Reynolds numbers –, jet mouth-to-surface distances 1–4 times the jet nozzle diameter, and for helium-4, air, and carbon.

Mass transfer in a non-uniform impinging jet. by Myndert Trevor Scholtz Download PDF EPUB FB2

J.C. Hsieh, T.F. Lin, Effects of jet-to-disk separation distance on the characteristics of mixed convective vortex flow in an impinging air jet confined in a cylindrical chamber, International Journal of Heat and Mass Transfer, /masstransfer, 48,(), ().Cited by: A theoretical solution for the impingement flow of a jet with a parabolic velocity distribution is given.

Viscous generation and diffusion of vorticity in the jet were neglected. Experimental velocity and pressure distributions measured in an impinging jet of air originating with Poiseuille flow compare well with theory, thus justifying the Cited by: Steady confined laminar axisymmetric impinging flow of a Newtonian fluid is relevant in many situations, an important application being heat and mass transfer from a solid surface to an impinging jet.

Impingement jet cooling heat transfer with a two-dimensional and a circular nozzle enhanced by a rib was studied experimentally and numerically. The effect of a rib on heat transfer enhancement in the wall jet region of an impinging jet has been studied via mass transfer experiments conducted using a naphthalene sublimation.

Abstract. This Chapter summarises existing knowledge about near field of fluid jets impinging upon a solid wall. In particular, the chapter focuses attention on submerged jets (those having the same density as the surrounding more or less stationary outside fluid) in which the impingement is complicated by vortical structures formed due to hydrodynamic instability on the jet outer edge.

Francesc Giralt, Olev Trass, Mass transfer in a non-uniform impinging jet. book transfer from crystalline surfaces in a turbulent impinging jet. part 2: Erosion and diffusional transfer, The Canadian Journal of Chemical Engineering, /cjce, 54, 3, (), ().

Key Words: jet impingement heat transfer, turbulence models, multiple jets, jet Reynolds number. INTRODUCTION Impingement heat transfer has emerged as a principle source for both controlled cooling and heating of a target surface because of its exceptional ability to enhance heat and mass transfer in a variety of industrial processes.

Jet. For the impingement/effusion cooling with orthogonal orientation, the low and non-uniform heat/mass transfer occurs between the effusion holes because the impinging jet is deflected by the.

An analysis based on the Chilton—Colburn analogy has been used to correlate the rate of mass transfer to the impingement and boundary layer regimes of an unsubmerged circular impinging jet.

The average mass transfer rate on the impinged surface was measured with a limiting current technique for a range of the nozzle Reynolds numbers from   Reduction of mean transfer coefficients by unfavorable outlet flow conditions. l/Lo = number of holes (jets) in outlet flow direction [4].

IMPINGING FLOWHEAT JET AND MASS TRANSFER 41 (or holes) with irregular spacing due to outlet channels may be used to find an upper and a lower limit for the transfer coefficients.

sublimation technique to analyze mass transfer coefficients due to an impinging slot jet in the laminar region. A mass-heat transfer analogy was used to convert mass transfer results into heat transfer results.

Miyazaki and Silberman (21) analyzed theoretically the two-dimensional laminar jet impinging. This is the second part of a survey summarizing authors’ research over a period of two decades on enhancing impinging jet heat and/or mass transfer by periodic unsteadiness of nozzle flow rate.

REVIEW A review of heat transfer data for single circular jet impingement K. Jambunathan, E. Lai, M. Moss* and B. Button Department of Mechanical Engineering, Nottingham Polytechnic, Nottingham, U K Experimental data for the rate of heat transfer from impinging turbulent jets with nozzle exit Reynolds numbers in the range of 5, have been collated and critically.

There have been several experimental, numerical and analytical investigations on single jet impingement. Viskanta has given a broad review of the heat transfer and flow mechanisms of single and multiple gas and flame jets.

The flow structure of an impinging jet can be divided into three regions as shown in Fig. 1: (a) free jet region which forms between the nozzle exit and the region before. Consideration is given to velocity profiles similar to that for a fully developed laminar channel flow.

The velocity field within the impinging jet is solved for within the framework of an inviscid flow model. Results from the inviscid solution are used as input for the analysis of the boundary layer heat or mass transfer on the impingement.

from an impinging jet to the stagnation region on a circular disk electrode. They found that there is a uniform accessibility to mass transfer (the thickness of concentration boundary layer and mass transfer rate have constant values) in a range of R/d (; 1) for turbulent nozzle flow.

Heat and Mass Transfer Conference JanuaryPaper No: IIT Guwahati, India Heat Transfer by Impingement of Circular Free-Surface Liquid Jets John H. Lienhard V Department of Mechanical Engineering Massachusetts Institute of Technology Cambridge MA USA email: [email protected] Abstract This paper reviews several aspects of.

The mass transfer rate was characterized by an etching method in a cupric chloride etching solution and jet instabi lity on the etching rate within the central impingement zone was discussed Chen et al.

[7] investigated experimentally the mass transfer between an impinging jet and a rotating disk The naphthalene sublimation technique was used. A major disadvantage of impinging jet-array is that the spatial heat transfer variations over impinging surface could be highly non-uniform.

Therefore, the flow and geometrical parameters of a multiple-jet system have to be carefully selected in order to provide the required heat transfer rates with acceptable uniformity over the impinging surface. The heat transfer is assumed to be the superposition of three components: heat flow to the steam, heat flow to the dispersed mist, and heat flow to the impinging droplets.

The latter is modeled as heat flow to a spherical cap for a time dependent on the droplet size, surface tension, impact velocity and surface temperature. The heat transfer between an axisymmetrical free impinging jet and a solid flat surface with nonuniform wall temperature or wall heat flux is investigated, solving both the exact energy equation and the boundary layer energy equation asymptotically in the vicinity of the stagnation point.

Increasing the wall temperature or wall heat flux with the radial distance (r) is shown to reduce the. The aim of this experimental study is to investigate the heat (mass) transfer of a rotating disk with an impinging circular jet.

To facilitate the experiments, the naphthalene sublimation technique was employed. In order to analyze the results, measurements of the heat (mass) transfer of a stationary disk with an impinging jet and a rotating disk without jet impingement were also made.

Effects of Non-uniform Heat Transfer in a Tempering Process on Glass Quality M., Heat and Mass Transfer between Impinging Gas Jets and Solid Surfaces, Advances in Heat Transfer, vol. 13, pp.R., Heat Transfer of Impinging Jet: Effect of Compressibility and Turbulent Kinetic Energy Production, IX International Conference on.

Details about Fundamentals of Heat and Mass Transfer: With Wiley’s Enhanced E-Text, you get all the benefits of a downloadable, reflowable eBook with added resources to make your study time more entals of Heat and Mass Transfer 8th Edition has been the gold standard of heat transfer pedagogy for many decades.

Complementary mass-transfer imaging experiments, in which the transport-limited current at the UME is monitored as a function of the nozzle position, as a jet of solution is scanned over the electrode surface in a raster pattern, are shown to provide useful information on the positioning requirements of the MJE and a unique insight into the.

The effect of jet inclination on the heat transfer is investigated experimentally for the case of a round, single-phase free liquid jet impinging on a flat, constant heat-flux surface. Effects of Acoustic Excitation Positions on Heat Transfer and Flow in Axisymmetric Impinging Jet: Main Jet Excitation and Shear Layer Excitation Int.

Heat Fluid Flow X. This paper describes the characteristics of the heat transfer and flow of a swirling laminar impinging jet in a comparatively narrow space with a confined wall.

Air is impinged on a flat surface with constant wall temperature. The heat transfer and flow field were analyzed numerically by solving three-dimensional governing equations. Heris, S.Z., Etemad, S.G. and Esfahany, M.N.

() Experimental Investigation of Oxide Nanofluids Laminar Flow Convective Heat Transfer. International Communications. The local heat transfer from a small heat source to a normally impinging, axisymmetric, and submerged liquid jet, in confined and unconfined configurations, was experimentally investigated.

A single jet of FC issuing from a round nozzle impinged onto a square foil heater, which dissipated a constant heat flux. J. M. Buchlin / JAFM, Vol. 4, No. 2, Issue 1, pp.incompressible gas jets and solid surfaces.

The single and multiple jet systems are successively considered. The flow and.of impinging jets heat transfer Abstract This work compares a number of CFD transient models of an impinging jet. The specific case considered is an impinging jet with z/D = 6 and Re The variables tested are: Turbulence model (LES, k-ε, V2F and DES), discretization schemes, mesh density and.[12] Zumbrunnen D.

A.,“ Convective Heat and Mass-Transfer in the Stagnation Region of a Laminar Planar Jet Impinging on a Moving Surface,” ASME J.

Heat Transfer,pp. –/